Leggera teamed with FCA, Grammer AG-TMD Group and DuPont on this award-winning Wrangler Spare Tire Carrier Assembly, which represents a significant innovation in technology. The previous production design employed a die-cast magnesium structure with integral steel reinforcements required to maintain strength during impact. However, this structure created a significant risk for galvanic corrosion, quality concerns and warranty issues.

Mg Thixomolded Inner Carrier

Nylon 66 Overmolded Outer Carrier

New Tire Carrier

“The market for sophisticated systems is rapidly expanding and we are challenged by vehicle manufacturers to incorporate multiple functions, materials and components in their systems,” says Nathan Sanko, CEO of Leggera Technologies. “Leggera’s leadership position in automotive systems gives us the opportunity to collaborate in developing the solutions to meet this challenge.”

The 2018 Wrangler Spare Tire Carrier employs a thixomolded magnesium (Mg) core that is protected and strengthened by an overmolded Nylon 66 skin. Thixomolding is required because of unacceptable tolerances associated with die-cast magnesium. The overmolding process secures the magnesium with a tough nylon skin, which virtually eliminates the galvanic corrosion issues associated with the prior production part. However, the benefits of overmolding do not end with resistance to corrosion. The exterior grade, toughened by DuPont’s Nylon 66, also acts as a shock absorber to improve impact resistance acting as a “composite” structure while also allowing the outside surface to be textured an/d color matched to other molded components.

Replacing cast magnesium with thixomolded magnesium increased ductility by 10 percent, reduced weight with an efficient structure that is unachievable with die-casting and integrated shroud to protect the review camera at a cost savings of nearly $15 per vehicle compared to die-casting.

A full thermoplastic CHMSL carrier assembly was used. The shape was optimized to use a Nylon 66, 50 percent glass-reinforced polymer on the main structure, providing the necessary support and flexibility to lower the rear wiper drive and increase rear visibility. Moving the wiper drive significantly improved rear visibility compared to the previous model. The high glass content on one half also meant that an unfilled ASA resin could be used on the other side allowing for a textured, color-matched, class-A view from the passenger compartment, while also concealing the wire harness.

“Leggera is committed to providing our customers with cutting-edge technology, innovative processes and quality products through our proven systems and industry partnerships. We anticipate a tremendous future for magnesium thixomolded applications,” says Boney Mathew, COO of Leggera Technologies. “Our relationship with OEMs such as FCA can significantly advance the acceptance of new methods of integration and will benefit our development and manufacturing efforts.”

About Leggera Technologies LLC

Leggera Technologies, headquartered in Auburn Hills, Michigan, employs engineers with OEM-level experience, so they understand its OEM customers’ needs. The company’s precision injection molded magnesium technology (thixomolding) is perfectly suited to the needs of OEMs in today’s environment. Although thixomolding uses magnesium as its source material, it is distinct from die-cast magnesium. Thixomolding delivers net shaped parts, superior material properties, incredibly tight tolerances, thinner walls and lower draft angles, resulting in stronger, lighter weight parts compared to die-casting. Leggera focuses on structural automotive parts, such as cross car beams, inner closures and steering column mounts. Leggera provides the greatest value in re-designing or designing from scratch a magnesium solution where the incumbent part is either die-cast magnesium, aluminum or steel, particularly if they are multiple part assemblies than can be combined and molded as a single part. For more information, visit http://www.leggeratech.com.